Analysis of tissue neogenesis in extraction sockets treated with guided bone regeneration: clinical, histologic, and micro-CT results.

The aims of this article were to perform a detailed evaluation of the healing of extraction sockets covered with a resorbable collagen membrane 12 weeks following exodontia and to determine if this device had ossifying properties. Ten consecutive subjects in need of extraction of maxillary premolars were recruited. Each subject had a hopeless maxillary premolar extracted with minimal trauma. Sockets were then covered with a collagen barrier membrane alone. At 12 weeks, reentry surgery was performed, clinical measurements were repeated, and bone core biopsies were obtained prior to dental implant placement for histologic and microcomputed tomography (micro-CT) analysis. Study sites showed mean bone regeneration horizontally of 7.7 mm (buccopalatally) and 4.6 mm (mesiodistally). Vertical bone repair showed a mean gain of 10.9 mm. Subtraction radiography showed a mean apical shift of the crestal bone at the center of the socket of 2.1 mm (range, 0.7 to 4.3 mm). Micro-CT and histology revealed formation of well-mineralized tissue at 12 weeks, with a mean percentage of vital bone of 45.87% ± 12.35%. No signs of membrane ossification were observed. A detailed analysis of tissue neogenesis in extraction sites protected by this barrier membrane has demonstrated that adequate bone formation for implant placement occurs as early as 12 weeks following exodontia, with minimal changes in alveolar ridge dimensions. No evidence of membrane ossification was observed.